India’s telecom network — the second-largest in the world, after the United States — is largely made up of cellphone connections and is releasing substantial amounts of harmful pollutants and greenhouse gases into the atmosphere.

So say the first-ever emission estimates from this sector, released jointly by the Germany-based Institute of Energy and Climate Research – Troposphere and the Indian Institute of Tropical Meteorology (IITM), Pune. The study was published in the January issue of Atmospheric Environment, an international peer-reviewed journal.

Here’s how it works. With erratic power supply across the country, base transceiver stations — the towers that facilitate wireless communication — are run partly on diesel generators, a source of highly toxic pollutants.

These direct pollutants — and the pollution emitted by coal-fired power plants while generating power for the towers — are together spewing tonnes of particulate matter, nitrogen oxide, carbon dioxide, sulphur dioxide, carbon monoxide, black carbon and hydrocarbons into the atmosphere every year.

With the number of wireless phones in use spiralling upwards from 261.8 million in 2008 to 893.6 million in 2011 the number of wireless telecom towers in India has gone from 1.78 lakh to 8.60 lakh.

And diesel consumption at these towers has shot up from 2 billion litres in 2007 to an estimated 7.5 billion litres a year in 2011.

As a result, the study found, emissions from the generation of electricity consumed by wireless networks saw a nine-fold increase between 2008 and 2011.

“These emissions are directly linked to air quality pollution and associated health impacts,” said Saroj Kumar Sahu, lead investigator at the Institute of Energy and Climate Research – Troposphere. “Our major concern is that these emissions are affecting the relatively clean atmosphere in rural India, and if no remedial measures are taken, future emissions could almost double by 2020.”

As more people buy wireless phones, researchers estimate that 3 lakh new towers will be needed by 2020, leading to further increases in harmful emissions.

If the impact on air quality is to be lessened, they say, the diesel generators will need to be replaced with renewable energy sources or at least more power supply from the grid.

“Investing in low-emission technology could therefore constitute an important element for improving air quality in rural areas, where most of the future telecom growth is expected,” said Gufran Beig of IITM.

The industry has been taking steps to reduce power consumption, says Rajan Mathews, director general of the Cellular Operators Association of India.

“These measures include improved electronic equipment, using solar energy, running towers without air-conditioning and replacing old batteries with energy-efficient ones.”